The invention relates to a home appliance, in particular a washing machine, a washing machine having dryer function or dryer, comprising a telescopic-type damper having a displacement sensor module mounted thereon.
EP 1 220 961 B1 discloses a damper for a washing machine. The damper comprises a piston movable in a cylindrical housing and a device to measure the position of the piston inside the housing. According to one embodiment, the device comprises a coil unit wound around the housing of the damper and a sensor element located at the end of the piston, which is located inside the cylindrical housing. The sensor element is made of metal, e.g. iron. The coil unit is connected by wire to an evaluating unit of the washing machine, which is located at an inner wall of the casing of the washing machine. When the piston and therefore the sensor element of the damper moves, e.g. due to loading the washing machine with laundry, the sensor element changes the inductivity of the coil unit. As the change of inductivity is proportional to the penetration depth of the piston into the coil unit, the travel path length of the piston can be determined by the evaluating unit.
WO 2008/012651 A2 discloses a household appliance, like a washing machine, with a displacement sensor. The displacement sensor measures the relative displacement between a cylinder and a piston of a damper for a washing group of a household appliance. According to one embodiment, a coil is wound around the cylinder of a damper and is connected by wire to an electronic detection module, which is fixed to the cylinder with screws. At least a part of a piston of the damper, which is located inside the coil, comprises ferromagnetic material, wherein the value of the inductance of the coil depends on the axial penetration of the piston within the volume of the coil. Further, the electronic detection module comprises an oscillator circuit, the oscillation frequency of which depends on the impedance of the coil on the damper cylinder. The relative displacement of the cylinder and piston is determined by the electronic detection module as a function of the oscillator circuit. A microcontroller included in the electronic detection module locally processes the signal output of the oscillator unit in order to obtain the relative displacement and additionally or alternatively any other physical quantities associated with the relative displacement, like the weight of laundry placed inside the drum of the washing group.